Experiment design ideas
Are some colours encoded faster than others? 03.09.2013 Based on this paper: Parsons, Novich & Eagleman (2013). Motor-sensory recalibration modulates perceived simultaneity of cross-modal events at different distances. Sound is processed faster than visual information. Therefore the brain must synchronise sound and vision so that they appear to occur at the same time. There is a window of ~80ms, in which sound and visual information are perceived to happen at the same time. i.e. if a sound input is presented 80ms after a visual input, they are perceived to have happened at the same time. Experiment idea. Present a tone, followed by a colour, and ask participants to respond with a key press if the tone and colour were presented at the same time, or one after the other. For each colour used, vary the delay from 0ms, 10ms, 20, 30.. etc.. Those colours which are processed slower should show lower accuracy at shorter delays. Is automatic visual attention directed more so by particular dimensions of a feature (i.e. particular colours, or particular geons)? 02.09.2013 Ask participants to view a computer screen while tracking their eye movements. Present images on the screen for short periods of time. Half of these will be black and white distractor images. The other half will be displays of either basic shapes or colours, equal distance from the centre of the screen. Record which features they fixate to first. Out of arrays of colours, they may fixate to particular colours more often than others, and out of arrays of shapes, they may fixate to particular shapes more so than others. automatic visual attention directed more so by particular sub-types of a feature (i.e. particular colours, or particular geons). Is overt selective attention driven by particular features (e.g. locations, colours or shapes etc.)? Experiment one. Give participants a visual search task, in which a display appears containing various feature conjunctions. Every object consists of the two same features (e.g. colour and shape). However there will be two objects which are different from the rest: *Object 1: Both colour and shape is different from the rest of the objects, this is the correct response. Participants respond by clicking the object with their mouse. *Object 2: One feature is different from every other object, and one feature is the same as every other object. If colours direct attention, then reaction times will be slower when object 2 has a different colour, but the same shape. If shape directs attention, then reaction times will be slower when object 2 has a different shape, but the same colour. By getting participants to select the correct response with a mouse click, it may be possible to analyse the mouse movement curve? Maybe also we could track their eye gaze data as well? Experiment two. An alternative approach would be to use a matching task. Display two objects at a time on the screen, and to ask participants to judge whether they are the same object or not, under time pressure. Condition one: Both have same colour and shape. Condition two: Both have same shape, but different colour. Condition three: Both have a different shape, but the same colour. Condition four: Both have a different colour and shape. Do some features gain priority during encoding over others? Participants are given a working memory task, where they first view a to-be-remembered (TBR) array, consisting of colours shapes, followed by a probe array after a short delay. They must indicate whether or not the probe array matches the TBR array. There will be three conditions in the TBR array: Condition one: Each object has a unique shape and a unique colour. Participants are able to encode both shape and colour. Condition two: All objects are the same shape, but each has a unique colour. Participants are able to encode colour, but encoding shape has no value in distinguishing the objects (i.e. colour is diagnostic). Condition three: Each object has a unique shape, but all objects share the same colour. Participants are able to encode shape, but encoding colour has no value in distinguishing the objects (I.e. shape is diagnostic. The test array will have the following conditions: Exact match: If the TBR array was condition one, the shapes and colours in the test array match those in the TBR array. Colours match: If the TBR array was in condition two, each shape will be unique and will not match those in the TBR array. The colours in the test array will match those in TBR array. Shapes match: If the TBR array was in condition three, the shapes will match those that were in the TBR array. Each object will have a unique colour, but will not match those in the TBR array. No-match: Each object has a unique colour and shape, but they do not match those in the TBR array. Do some features gain priority during retrieval over others? This experiment would be the reversal of the procedure for question four. Participants would view a TBR array, and every object would always consist of unique colours or shapes. This way, participants can encode both features, but they do not know which features they will need to retrieve until they see the test array. The test array will consist of the following conditions: Condition one: Each object has a unique shape and a unique colour. Participants are able to recall either shape or colour to make the comparison between the TBR array and the test array. Condition two: Every object has the same shape, a shape which was not present in the TBR array, but the colour of the objects match those that were in the TBR array. Retrieving shape would not give them any diagnostic information, but colour would. Condition three: The shape of the objects match those of the TBR array, but all objects are the same colour, a colour which was not present in the TBR array. Retrieving colour does not have any diagnostic information, and participants must retrieve shape to make the comparison. Other possible future experiments 02.09.2013 reward experiment. Is attention directed by features, or objects with meaning? **#The effect of updating conjunctions in memory on the strength of feature binding. **#Is it possible to control which features the system prioritises? **#How does control which feature the system prioritises affect the encoding of other features? e.g. does it aid or impede them? In other words, are the features processed serially or in parallel?